DENVER, COLORADO AND MADISON, WI – Dr. Laura Strong of Quintessence Biosciences, Inc. presented information about one of the company’s EVade™ Ribonuclease development programs at the annual meeting of the American Association for Cancer Research. Dr. Strong presented data from conjugates produced using the clinical candidate QBI-139 and polyethylene glycol (PEG).

QBI-139 is a potent anticancer agent based on the company’s EVade™ Ribonuclease technology. The technology provides an opportunity to attack RNA, an exciting new drug target, in cancer cells with analogs of the human pancreatic ribonuclease 1. In preclinical disease models, QBI-139 has shown a strong tolerability profile and outstanding tumor growth inhibition in vivo against human pancreatic, non-small cell lung, prostate, and ovarian solid tumors. QBI-139 is currently in a solid tumors Phase I human clinical trial being conducted at the University of Wisconsin Madison Comprehensive Cancer Center.

“The success of the next generation of Evade™ Ribonuclease products significantly broadens the potential impact of our technology,” said Quintessence Biosciences CEO Ralph Kauten. “Conjugates of EVade™ Ribonucleases provide a means to extend the utility of a clinically validated approach to cancer treatment.”

About Quintessence Biosciences, Inc.

Quintessence Biosciences, Inc. is a private biopharmaceutical company focused on development of proprietary cancer therapies based on the EVade™ Ribonuclease technology. Quintessence’s first product candidate, QBI- 139, is in a Phase 1 clinical trial at the University of Wisconsin Comprehensive Cancer Center. The company also has a pipeline of other EVade™ Ribonuclease products in preclinical research. For more information, visit www.quintbio.com.

About the American Association for Cancer Research Annual Meeting

The AACR 100th Annual Meeting 2009, April 18-22 is being held in Denver, Colorado. The AACR Annual Meeting attracts more than 17,000 participants who share the latest discoveries and developments in the field. The theme, "Science, Synergy, and Success," will highlight the best cancer science and medicine from institutions all over the world. The AACR expects to showcase more than 6,000 outstanding proffered papers and hundreds of invited talks from the global community of experts in today's cancer research, representing clear evidence of the enormous progress that has been made over the years in the understanding, treatment, and prevention of cancer.